A novel acid-free leaching route of recovering Li2CO3 and FePO4 from spent LiFePO4 black powder

Abstract

With the rapid increase in the usage of lithium ion batteries, recovering Li2CO3 from LiFePO4 black powder has become an issue of public concern. Nowadays, the widely used acid leaching technology has some obvious disadvantages, such as complex recovery process, serious equipment corrosion and unavoidable secondary pollution. In this work, a novel acid-free leaching route of recovering Li2CO3 and FePO4 from LiFePO4 black powder is proposed. This novel route does not include inorganic or organic acid leaching, complex pH adjustment and wastewater treatment processes. After optimizing the technological conditions, Li2CO3 and FePO4 with high purity are recovered with high recovery rate of over 96%. Then, the recovered Li2CO3 and FePO4 are used as iron and lithium sources to regenerate LiFePO4 and the electrochemical performances are compared in detail. When the molar ratio of Li2CO3:FePO4:C6H12O6 (glucose) is 1.03:2:0.35, the regenerated LiFePO4 (R-LFP-0.35) cathode displays the optimal electrochemical performance with the discharge capacity of 163.9 mAh g−1 at 0.1 C, 120 mAh g−1 at 4 C and excellent capacity retention ratio of 98.0% after 100 cycles at 0.2 C. This work provides a new green and environmentally friendly strategy for the recycling of LiFePO4 black powder.